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Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.action.search;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.util.concurrent.CountDown;
import org.elasticsearch.search.SearchPhaseResult;
import org.elasticsearch.search.SearchShardTarget;
import java.util.function.Consumer;
/**
* This is a simple base class to simplify fan out to shards and collect their results. Each results passed to
* {@link #onResult(SearchPhaseResult)} will be set to the provided result array
* where the given index is used to set the result on the array.
*/
final class CountedCollector {
private final Consumer resultConsumer;
private final CountDown counter;
private final Runnable onFinish;
private final SearchPhaseContext context;
CountedCollector(Consumer resultConsumer, int expectedOps, Runnable onFinish, SearchPhaseContext context) {
this.resultConsumer = resultConsumer;
this.counter = new CountDown(expectedOps);
this.onFinish = onFinish;
this.context = context;
}
/**
* Forcefully counts down an operation and executes the provided runnable
* if all expected operations where executed
*/
void countDown() {
assert counter.isCountedDown() == false : "more operations executed than specified";
if (counter.countDown()) {
onFinish.run();
}
}
/**
* Sets the result to the given array index and then runs {@link #countDown()}
*/
void onResult(R result) {
try {
resultConsumer.accept(result);
} finally {
countDown();
}
}
/**
* Escalates the failure via {@link SearchPhaseContext#onShardFailure(int, SearchShardTarget, Exception)}
* and then runs {@link #countDown()}
*/
void onFailure(final int shardIndex, @Nullable SearchShardTarget shardTarget, Exception e) {
try {
context.onShardFailure(shardIndex, shardTarget, e);
} finally {
countDown();
}
}
}